Deep skin wound healing and remodelling in porcine models using combined urinary bladder matrix powder and sheet

Objective: Conventional therapeutic approaches frequently fail to achieve optimal healing and scar reduction in the management of certain extensive and deep wounds. Acellular porcine urinary bladder matrix (UBM) has demonstrated favourable clinical outcomes in tissue regeneration. This study aims to investigate the therapy advantages of combined UBM powder and sheet, and elucidate its whole healing process in comparison to a collagen sponge, using a full-thickness skin defect porcine model. Method: Using a full-thickness skin defect porcine model, the porcine urinary bladder was decellularised and lyophilised, then characterised by mass spectrometry for composition analysis. In this model, 4.0×4.0cm full-thickness dorsal wounds were created and randomly divided into three treatment groups: UBM powder and sheet; collagen sponge (Pelnac; Gunze Limited, Inc., Japan); and paraffin gauze (Zhende Medical, China). Wound healing processes were evaluated at two, four and eight weeks post-surgery by gross observation and histopathological staining, as well as immunohistochemical staining of Ki-67, CD31, collagen IV and laminin to assess their expression levels. Tissue regeneration and remodelling were evaluated based on nascent collagen structure and scar degree at eight weeks post-surgery Results: The acellular UBM biological material contained an abundance of protein compositions, which are conducive to tissue regeneration. Combined therapy of UBM improved the healing rate and quality, associated with greater expression of Ki-67, CD31, collagen IV and laminin at two weeks post-surgery. Remodelling results demonstrated superior collagen weave structure and smaller scar area using UBM. Conclusion: In this porcine model, combined therapy of UBM powder and sheet improved deep skin wounds healing and remodelling, making it a promising option for the treatment of deep wounds.